Procedures for the synthesis of ethylenediamine bisborane and ammonia borane

Abstract

A method for synthesizing ammonia borane includes (a) preparing a reaction mixture in one or more solvents, the reaction mixture containing sodium borohydride, at least one ammonium salt, and ammonia; and (b) incubating the reaction mixture at temperatures between about 0° C. to about room temperature in an ambient air environment under conditions sufficient to form ammonia borane. Methods for synthesizing ethylenediamine bisborane, and methods for dehydrogenation of ethylenediamine bisborane are also described.

The invention claimed is: 
     
       1. A method for synthesizing ammonia borane comprising:
 preparing a reaction mixture in one or more solvents, the reaction mixture comprising sodium borohydride, at least one ammonium salt, and ammonia, wherein the concentration of ammonia in the solvent is between about 1 to about 10% v/v; and 
 incubating the reaction mixture at temperatures between about 0° C. to about room temperature in an ambient air environment under conditions sufficient to form ammonia borane. 
 
     
     
       2. The method of  claim 1 , wherein the at least one ammonium salt is selected from the group consisting of ammonium sulfate, ammonium chloride, ammonium fluoride, ammonium carbonate, ammonium nitrate, ammonium acetate, ammonium bicarbonate ammonium carbamate, ammonium perchlorate, ammonium hydrogen fluoride, ammonium phosphate, and ammonium hydrogen sulfate. 
     
     
       3. The method of  claim 1 , wherein the ratio of sodium borohydride to ammonium salts used is between about 1:1 to about 1:4. 
     
     
       4. The method of  claim 1 , wherein the solvent is THF. 
     
     
       5. The method of  claim 1 , wherein the conditions are formulated for synthesizing ammonia borane at a yield of >50%. 
     
     
       6. The method of  claim 1 , wherein the conditions are formulated for synthesizing ammonia borane at a purity of >90%. 
     
     
       7. A method for synthesizing ammonia borane comprising:
 preparing a reaction mixture in one or more solvents, the reaction mixture comprising sodium borohydride, at least one ammonium salt, and ammonia, wherein the concentration of ammonia in the solvent is between about 2.5 to about 5% v/v; and 
 incubating the reaction mixture at temperatures between about 0° C. to about room temperature in an ambient air environment under conditions sufficient to form ammonia borane. 
 
     
     
       8. The method of  claim 7 , wherein the at least one ammonium salt is selected from the group consisting of ammonium sulfate, ammonium chloride, ammonium fluoride, ammonium carbonate, ammonium nitrate, ammonium acetate, ammonium bicarbonate ammonium carbamate, ammonium perchlorate, ammonium hydrogen fluoride, ammonium phosphate, and ammonium hydrogen sulfate. 
     
     
       9. The method of  claim 7 , wherein the ratio of sodium borohydride to ammonium salts used is between about 1:1 to about 1:4. 
     
     
       10. The method of  claim 7 , wherein the solvent is THF. 
     
     
       11. The method of  claim 7 , wherein the conditions are formulated for synthesizing ammonia borane at a yield of >50%. 
     
     
       12. The method of  claim 7 , wherein the conditions are formulated for synthesizing ammonia borane at a purity of >90%.